Extension of pre-existing infections of the face, lacrimal sac, and lacrimal gland which can extend into the orbit

Pathophysiology: The most common bacterial pathogens in preseptal cellulitis include Haemophilus influenza, Staphylococcus aureus, and Streptococcus pneumoni

Therapy: Subperiosteal abscess formation should be suspected if patients fail to improve or deteriorate on intravenous antibiotics .

Infants with preseptal cellulitis are usually admitted for intravenous therapy, whereas

older children and adults with preseptal infections might possibly be treated with oral antibiotics. 7- to 10-days of intravenous therapy are required, followed by a course of oral antibiotics for 10 to 14 days

infection posterior to orbital septum

90% from extension of acute or chronic bacterial sinusitis, remainder s/p trauma or surgery or 2o to extension from other orbital or periorbital infection, or endogenous w/septic embolization